英语中表示强调的结构是 “ It is (was) 被强调的部分＋that (who) 句子的其它部分，除了谓语部分外，其余的可以用于强调句。需要注意的是当强调的部分是时间状语或地点状语时，只能用that而不用when 或where； 当被强调的部分是人时，可以用who； 当强调主语时要注意主语和谓语的一致。
It is my uncle that/who is coming to visit us.
It was at midnight that he came back home.
It was in the park that the two old friends ran into each other.
It’s not you who are in trouble. but it’s I who am in trouble.
It was not until the accident happened that I became aware of my own foolishness
直到事故发生了我才意识到自己的愚蠢。